Retroreflector for the reflection of electromagnetic rays

ABSTRACT

Retroreflector for the reflection of electromagnetic rays suitable for destroying, by reflection or absorption, electromagnetic radiation, which could lead to a lasting detrimental influencing of magnetic or other data carriers. The retroreflector is constructed as a flat article formed from a base layer of metallic, juxtaposed reflectors with filter coatings applied thereto formed from a suitable metallic material, and provided with top coatings on a bottom surface and a top surface of the base layer.

BACKGROUND OF THE INVENTION

The present invention relates to a retroreflector for reflectingelectromagnetic rays, which is suitable for destroying, by reflection orabsorption, electromagnetic radiation, which could lead to a lastinginfluencing on magnetic or other data carriers, particularly as aprotective device for data memories.

In modern computing and data processing installations, memories are usedfor storing information. These memories are, for example, constructed incentral processing units of data processing installations or used asexternal memories. Use is generally made of the laws of electromagnetismfor storing information. Thus, magnetic core, tape, bubble and drummemories are known.

In such memories, and, in particular, in read-only memories, informationis frequently stored which is only present therein and to which no otheraccess is possible. It has therefore proved to be a problem to protectsuch memories against damage and hence the destruction of the storedinformation material. It has admittedly already been proposed to arrangesuch memories in building rooms in which mechanical influencing of thememories is largely excluded. However, even in these rooms, it is notpossible to ensure a completely effective protection against detrimentalinfluences or destruction of the memories by the action ofelectromagnetic radiation.

Thus, if a velocity-modulated tube of corresponding power level isoperated in the vicinity of a data memory, the electromagnetic radiationfrom the tube can detrimentally influence and/or destroy the datamaterial, so that on again obtaining access to the data, it isestablished that the data memories only contain inadequate or noinformation.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a retroreflector forreflecting electromagnetic rays, which is suitable for destroying, byreflection or absorption, electromagnetic radiation, which could have alasting detrimental influence on magnetic or other data carriers, saidretroreflector being locatable in the area around data carriers, so asto bring about a complete shielding of said data carriers againstelectromagnetic radiation.

According to the invention this object is achieved by a retroreflectorof the aforementioned type, wherein the retroreflector is constructed asa flat article formed from a base layer of metallic, juxtaposedreflectors with filter coatings of a suitable metallic material appliedthereto and with a top coating on the top and bottom surfaces thereof.

This retroreflector provides the possibility of offering optimumprotection to data memories of any type against the detrimentalinfluence of electromagnetic radiation, because with the aid of such aretroreflector, retroreflection takes place of the most varied wavetypes. With the reflectors in the base layer, a high reflection of theimpacting electromagnetic radiation is achieved, in the manner of atriple or corner mirror in optics. As a result of the juxtaposedindividual reflectors, they, in each case, act as a retrodirectivereflector, a diffuse reflection only being obtained from the connectingedges of the individual reflectors. In order to bring about a reflectionof all the wavelengths in question, e.g. from the X, S and VHF waveranges, correspondingly formed filter coatings are provided on the baselayer. Additional protection by radiation absorption results from thetop coatings arranged on the top and bottom surfaces.

As a function of requirements, a foil constructed in this way can belocated at any point on a building and placed around a data memory insuch a way that a substantially secure protective sheath is obtained.

According to a preferred embodiment of the retroreflector, the baselayer is constructed as a metal foil or sheet with pyramid point-likeindentations or retractions with three boundary faces juxtaposed thereinwithout gaps, the boundary faces of each indentation have on theengaging edges an angle of α=90°.

The individual reflectors formed in this way, in which three edgesabutting in a corner form a right angle to one another ensure that eachindividual incident electromagnetic beam is reflected on all threesurfaces and travels back parallel to its direction of incidence. Thebase layer having the individual reflectors can be produced by stamping,punching, deep drawing, compression, etc., of a metal foil or sheet.

Preferably, the thickness of the filter coating is fixed in such a waythat a broad-band X, S and VHF wave filter is formed, while being madefrom a metal or precious metal. This permits a specific adaptation ofthe filter coatings to the characteristics of the expected radiation tobe reflected, the filter coatings preferably being formed from chromium,brass, silver and/or Mumetal (a high magnetic permeable iron alloy). Thefilter coatings can be individually arranged as prefabricated foils onthe base layer or are formed by evaporation onto the base layer.Preferably, the top coatings are formed in the same way.

According to a preferred embodiment for arrangement on building wallsand ceilings, the flat article is constructed as a surface-covering foilweb with a lower top coating, suitable for placing on a wall, and anupper top coating suitable for placing wallpaper or emulsion on the flatarticle.

This construction makes it possible to use the flat article in place ofwallpaper on room walls or ceilings and then apply conventionalwallpaper thereto. Thus, the optical appearance of the walls andceilings of rooms containing storage units is not altered, butnevertheless a high degree of protection is obtained. It is alsopossible to apply the flat article, e.g., to doors in this way.

According to a further preferred embodiment for arrangement placing onbuilding floors, the flat article is constructed as a surface-coveringfoil web with a lower top coating suitable for placing and fixing to afloor and with an upper top coating suitable for receiving a carpet pileand with a base layer for absorbing static loading forces.

In this construction of the flat article, it can be used in place of acarpet on the floor and the data memory or memories to be protected canbe placed thereon. Thus, with simple means, a comprehensive arrangementof a protective envelope in a building room is possible, without theouter appearance of such rooms changing and without impeding orhindering persons working in said room.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in greater detail hereinafter relative tonon-limitative embodiments and the attached drawings, wherein show:

FIG. 1: a diagrammatic view of a retroreflector.

FIG. 2: the retroreflector in a vertical sectional representation alongline II--II of FIG. 1.

FIG. 3: a reflection element in a larger-scale detail.

FIG. 4: the reflection element according to FIG. 3 in a view from above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIGS. 1 and 2, the flat article is designated 100 and comprises abase layer 10 on which are placed filter coatings formed either as foils50 or as evaporation deposited coatings 150. The corresponding topcoatings 30, 40, which serve as absorption coatings, are placed on thetop surface 10b and bottom surface 10a of the base layer 10.

FIGS. 3 and 4 show a reflector element 20 from base layer 10, and thereflector element 20 being formed in the latter by, for example, deepdrawing. Reflector element 20 is constructed as an indentation orretraction in base layer 10, said indentation being constructed inpyramidal point-like manner with three boundary faces 21, 22, 23. Thelatter are provided on their engaging edges 21a, 23a; 21b, 22a; 22b, 23bwith a reciprocal angle of precisely α=90°. As a result of thisarrangement of the limiting or indentation faces, a total reflection ofthe incident electromagnetic radiation is ensured. In the vicinity ofreflector elements 20, filter coatings 50, 150 are provided covering theboundary faces 21, 22, 23 or are produced thereon by evaporationdeposition. As shown by FIGS. 1 and 2, reflectors 20 in base layer 10are directly juxtaposed, so that a difficultly traversable layer for theelectromagnetic radiation is formed, on which layer 10, the additionalfilter coatings 50, 150 are arranged. At the top, base layer 10 iscovered by top coating 30, which is constructed in such a way thatwallpaper may be stuck or emulsion may be applied thereto. The lower topcoating 40 can be applied to walls, floors or ceilings with aconventional wallpaper paste or some other suitable adhesive, but canalso be provided with a self-adhesive coating. It is also possible toincorporate reinforcements into the base layer 10 ensuring that the flatarticle 100 can absorb corresponding static or dynamic loads.

What is claimed is:
 1. A retroreflector for reflecting electromagnetic rays, said retroreflector being suitable for destroying, by reflection or absorption, electromagnetic radiation which could be detrimental to magnetic or other data carriers, said retroreflector being constructed as a flat article comprising:a base layer formed from metal in the form of a metal foil or sheet, said baselayer having juxtaposed reflectors formed therein as pyramidal point-like indentations or retractions with three boundary faces juxtaposed therein without gaps, said boundary faces forming 90° angles therebetween at engaging edges thereof, filter coatings, made from chromium, brass, silver and/or Mumetal, being applied, as a prefrabricated foil or by evaporation deposition, on the boundary faces of the juxtaposed reflectors, said filter coatings having such a thickness that is suitable for broadband filtering of X, S and VHF band waves; and top coatings applied to an upper surface and a lower surface of said base layer, said top coatings being substantially planar and made from plastic, metal or precious metal suitable for absorbing electromagnetic radiation, said top coatings being applied as prefabricated foils or by evaporation deposition, wherein, for arranging on building walls and ceilings, said flat article is formed as a surface-covering foil web in which the top coating on the lower surface is suitable for application to a wall while said top coating on said upper surface is suitable for receiving wallpaper or an emulsion.
 2. A retroreflector for reflecting electromagnetic rays, said retroreflector being suitable for destroying, by reflection or absorption, electromagnetic radiation which could be detrimental to magnetic or other data carriers, said retroreflector being constructed as a flat article comprising:a base layer formed from metal in the form of a metal foil or sheet, said baselayer having juxtaposed reflectors formed therein as pyramidal point-like indentations or retractions with three boundary faces juxtaposed therein without gaps, said boundary faces forming 90° angles therebetween at engaging edges thereof, filter coatings, made from chromium, brass, silver and/or Mumetal, being applied, as a prefabricated foil or by evaporation deposition, on the boundary faces of the juxtaposed reflectors, said filter coatings having such a thickness that is suitable for broadband and filtering of X, S and VHF band waves; and top coatings applied to an upper surface and a lower surface of said base layer, said top coatings being substantially planar and made from plastic, metal or precious metal suitable for absorbing electromagnetic radiation, said top coatings being applied as prefabricated foils or by evaporation deposition, wherein, for arranging on building floors, said flat article is formed as a surface-covering foil web in which the top coating on said lower surface is suitable for application and fixing to said floors, and said top coating on said upper surface is suitable for receiving a carpet pile, said base layer being constructed for absorbing static loading forces without damage thereto. 